/*      $NetBSD: biosboot.c,v 1.36 2025/12/17 16:18:11 nia Exp $ */

/*
 * Copyright (c) 2009 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to the NetBSD Foundation
 * by Mike M. Volokhov. Development of this software was supported by the
 * Google Summer of Code program.
 * The GSoC project was mentored by Allen Briggs and Joerg Sonnenberger.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#ifdef __RCSID
__RCSID("$NetBSD: biosboot.c,v 1.36 2025/12/17 16:18:11 nia Exp $");
#endif

#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#if defined(HAVE_SYS_ENDIAN_H) || ! defined(HAVE_NBTOOL_CONFIG_H)
#include <sys/endian.h>
#endif
#include <sys/bootblock.h>

#if defined(DIOCGWEDGEINFO) && !defined(HAVE_NBTOOL_CONFIG_H)
#define USE_WEDGES
#endif
#ifdef USE_WEDGES
#include <sys/disk.h>
#endif

#include <err.h>
#include <fcntl.h>
#include <paths.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "map.h"
#include "gpt.h"
#include "gpt_private.h"

#define DEFAULT_BOOTDIR         "/usr/mdec"
#define DEFAULT_BOOTCODE        "gptmbr.bin"

static int cmd_biosboot(gpt_t, int, char *[]);

static const char *biosboothelp[] = {
        "[-A] [-c bootcode] [-i index] [-L label] [-b startsec]",
#if notyet
        "[-a alignment] [-b blocknr] [-i index] [-l label]",
        "[-s size] [-t type]",
#endif
};

const struct gpt_cmd c_biosboot = {
        "biosboot",
        cmd_biosboot,
        biosboothelp, __arraycount(biosboothelp),
        0,
};

#define usage() gpt_usage(NULL, &c_biosboot)

static struct mbr*
read_boot(gpt_t gpt, const char *bootpath)
{
        int bfd, ret = -1;
        struct mbr *buf;
        struct stat st;
        char *bp;

        buf = NULL;
        bfd = -1;

        if (bootpath == NULL)
                bp = strdup(DEFAULT_BOOTDIR "/" DEFAULT_BOOTCODE);
        else if (*bootpath == '/')
                bp = strdup(bootpath);
        else {
                if (asprintf(&bp, "%s/%s", DEFAULT_BOOTDIR, bootpath) < 0)
                        bp = NULL;
        }

        if (bp == NULL) {
                gpt_warn(gpt, "Can't allocate memory for bootpath");
                goto fail;
        }

        if ((buf = malloc((size_t)gpt->secsz)) == NULL) {
                gpt_warn(gpt, "Can't allocate memory for sector");
                goto fail;
        }


        if ((bfd = open(bp, O_RDONLY)) < 0 || fstat(bfd, &st) == -1) {
                gpt_warn(gpt, "Can't open `%s'", bp);
                goto fail;
        }

        if (st.st_size != MBR_DSN_OFFSET) {
                gpt_warnx(gpt, "The bootcode in `%s' does not match the"
                    " expected size %u", bp, MBR_DSN_OFFSET);
                goto fail;
        }

        if (read(bfd, buf, (size_t)st.st_size) != (ssize_t)st.st_size) {
                gpt_warn(gpt, "Error reading from `%s'", bp);
                goto fail;
        }

        ret = 0;
fail:
        if (bfd != -1)
                close(bfd);
        if (ret == -1) {
                free(buf);
                buf = NULL;
        }
        free(bp);
        return buf;
}

static int
set_bootable(gpt_t gpt, map_t map, map_t tbl, unsigned int i)
{
        unsigned int j;
        struct gpt_hdr *hdr = map->map_data;
        struct gpt_ent *ent;
        unsigned int ne = le32toh(hdr->hdr_entries);

        for (j = 0; j < ne; j++) {
                ent = gpt_ent(map, tbl, j);
                ent->ent_attr &= ~GPT_ENT_ATTR_LEGACY_BIOS_BOOTABLE;
        }

        ent = gpt_ent(map, tbl, i);
        ent->ent_attr |= GPT_ENT_ATTR_LEGACY_BIOS_BOOTABLE;

        return gpt_write_crc(gpt, map, tbl);
}

static int
biosboot(gpt_t gpt, off_t start, uint64_t size, u_int entry, uint8_t *label,
    const char *bootpath, int active)
{
        map_t mbrmap, m;
        struct mbr *mbr, *bootcode;
        unsigned int i;
        struct gpt_ent *ent;
        uint8_t utfbuf[__arraycount(ent->ent_name) * 3 + 1];

        /*
         * Parse and validate partition maps
         */
        if (gpt_hdr(gpt) == NULL)
                return -1;

        mbrmap = map_find(gpt, MAP_TYPE_PMBR);
        if (mbrmap == NULL || mbrmap->map_start != 0) {
                gpt_warnx(gpt, "No valid Protective MBR found");
                return -1;
        }

        mbr = mbrmap->map_data;

        /*
         * Update the boot code
         */
        if ((bootcode = read_boot(gpt, bootpath)) == NULL) {
                gpt_warnx(gpt, "Error reading bootcode");
                return -1;
        }
        (void)memcpy(&mbr->mbr_code, &bootcode->mbr_code,
                sizeof(mbr->mbr_code));
        free(bootcode);

        for (i = 0; i < __arraycount(mbr->mbr_part); i++)
                if (mbr->mbr_part[i].part_typ == MBR_PTYPE_PMBR)
                        mbr->mbr_part[i].part_flag = active ? 0x80 : 0;

        /*
         * Walk through the GPT and see where we can boot from
         */
        for (m = map_first(gpt); m != NULL; m = m->map_next) {
                if (m->map_type != MAP_TYPE_GPT_PART || m->map_index < 1)
                        continue;

                ent = m->map_data;

                /* first, prefer user selection */
                if (entry > 0 && m->map_index == entry)
                        break;

                if (label != NULL) {
                        utf16_to_utf8(ent->ent_name,
                            __arraycount(ent->ent_name), utfbuf,
                            __arraycount(utfbuf));
                        if (strcmp((char *)label, (char *)utfbuf) == 0)
                                break;
                }

                /* next, partition as could be specified by wedge */
                if (entry < 1 && label == NULL && size > 0 &&
                    m->map_start == start && m->map_size == (off_t)size)
                        break;
                /* next could be start sector specified by -b option */
                if (entry < 1 && label == NULL && size == 0 &&
                    m->map_start == start)
                        break;
        }

        if (m == NULL) {
                gpt_warnx(gpt, "No bootable partition");
                return -1;
        }

        i = m->map_index - 1;


        if (set_bootable(gpt, gpt->gpt, gpt->tbl, i) == -1)
                return -1;

        if (set_bootable(gpt, gpt->tpg, gpt->lbt, i) == -1)
                return -1;

        if (gpt_write(gpt, mbrmap) == -1) {
                gpt_warnx(gpt, "Cannot update Protective MBR");
                return -1;
        }

        gpt_msg(gpt, "Partition %d marked as bootable", i + 1);
        return 0;
}

static int
cmd_biosboot(gpt_t gpt, int argc, char *argv[])
{
#ifdef USE_WEDGES
        struct dkwedge_info dkw;
#endif
        int ch;
        gpt_t ngpt = gpt;
        off_t start = 0;
        uint64_t size = 0;
        int active = 0;
        unsigned int entry = 0;
        uint8_t *label = NULL;
        char *bootpath = NULL;

        while ((ch = getopt(argc, argv, "Ac:i:L:b:")) != -1) {
                switch(ch) {
                case 'A':
                        active = 1;
                        break;
                case 'c':
                        if (gpt_name_get(gpt, &bootpath) == -1)
                                goto usage;
                        break;
                case 'i':
                        if (gpt_uint_get(gpt, &entry) == -1)
                                goto usage;
                        break;
                case 'L':
                        if (gpt_name_get(gpt, &label) == -1)
                                goto usage;
                        break;
                case 'b':
                        if (gpt_human_get(gpt, &start) == -1)
                                goto usage;
                        break;
                default:
                        goto usage;
                }
        }

        if (argc != optind)
                return usage();

#ifdef USE_WEDGES
        if ((gpt->sb.st_mode & S_IFMT) != S_IFREG &&
            ioctl(gpt->fd, DIOCGWEDGEINFO, &dkw) != -1) {
                if (entry > 0)
                        /* wedges and indexes are mutually exclusive */
                        goto usage;
                start = dkw.dkw_offset;
                size = dkw.dkw_size;
                ngpt = gpt_open(dkw.dkw_parent, gpt->flags, gpt->verbose,
                    0, 0, 0);
                if (ngpt == NULL)
                        goto cleanup;
        }
#endif
        if (biosboot(ngpt, start, size, entry, label, bootpath, active) == -1)
                goto cleanup;
        if (ngpt != gpt)
                gpt_close(ngpt);
        return 0;
usage:
        usage();
cleanup:
        if (ngpt != gpt)
                gpt_close(ngpt);
        free(bootpath);
        free(label);
        return -1;
}